The disclosed invention relates to an antenna configuration that is configured to tune the frequency of transmission without using filters. The antenna configuration comprises a tunable multi-feed antenna configured to wirelessly transmit electromagnetic radiation. A signal generator is configured to generate a plurality of signals that collectively correspond to a signal to be transmitted. The plurality of signals have a phase shift or amplitude difference therebetween. The plurality of signals are provided to a plurality of antenna feeds connected to different spatial locations of the tunable multi-feed antenna. The values of the phase shift and/or amplitude difference define an antenna reflection coefficient that controls the frequency characteristics that the tunable multi-feed antenna operates at, such that by varying the phase shift and or amplitude difference, the frequency characteristics can be selectively adjusted.